The aim of my research is to investigate the effect of compost on microbial activity and cations in salt-affected clay soils. The study was conducted in differing quantities (0, 25, 50 t ha-1) irrigation with different salt concentrations (0, 600, 1800 mg l-1) with addition of soil conditioner at final stage. CO2 measurements showed that salt concentrations and compost/soil ratio had a slight impact on soil respiration. However, following the addition of soil conditioner, a dramatic increase in respiration was recorded with two spikes caused by a chemical reaction and a biological reaction separately. Total CEC was improved with compost addition and the combined factor of compost and salt. P, and K were increased proportional to compost levels, and Na and S were to both salt and compost. Other elements were controlled by competitions and interactions each other in soils, with decrease trends to the addition of compost and salt. Therefore, the effect of compost and salts on microbial activity and cations was observed over the course of a relatively short time, and compost had a higher influence on soil respiration and cations than salts with a significant interaction between salts and compost.